1. Field of the Invention
The present invention relates to a spectacle and contact lens selecting system and a method thereof, and in particular, to a spectacle and contact lens selecting system and a method thereof, which enable the selection of spectacles and contact lenses fitted to each person on a computer network.
2. Description of the Related Art
Conventionally known methods for selecting spectacles lenses are methods which utilize eyeball models. Well known eyeball models are the Gullstrand eyeball model and the Le-Grand eyeball model.
These eyeball models have been used entirely for the design and evaluation of spectacles lenses. For the design of spectacles lenses, one standard model prepared as an optical eye model would make it possible to design lenses having various powers for standard eyes. This is sufficient for the design irrespective of the eye structure of a person because he/she can select among spectacles lenses prepared in every power of 0.25 D by actually wearing them, thereby ensuring that he/she finds spectacles lenses suitable for correction. That is, selection is flexible.
Currently, on the other hand, to measure uncorrected or corrected vision, one goes to see an ophthalmologist or has his/her vision measured at spectacles shops using optometers.
Recently, for example, virtual malls are available over networks such as the Internet. However, none of the spectacles shops available in these virtual malls provides a system for measuring the uncorrected and corrected vision on an on-line basis.
However, to solely determine the power of spectacles lenses suitable for the eyes of an individual, an optical model such as the eyeball model assumed to be commonly applicable to everyone would cause significant error in optical calculation thereby making the determination impossible. The determination can be made only by constructing an eyeball model for each person.
Use of the conventional eyeball models will create the following problems.
Since the conventional eyeball model is based on measurements made on eyes of people from Europe and the United States, they cannot be used for constructing a model having values close to those obtained by measuring living eyes of other races, e.g., Japanese people. For example, Japanese have a smaller radius of curvature of the cornea than do people from Europe and the United States.
A model is prepared based on an average of measurements.
Literature shows that in such data, the depth of the anterior chamber of the eye varies with age or the length of the eye axis is correlated with the degree of myopia for low degrees of shortsightedness. Thus, it is necessary to construct an eyeball model according to the age and the degree of myopia of each individual.
Although the lens of the eye has a refractive index that is unevenly distributed, the average refractive index is used. The simplified double structure provided to the lens of the eye causes a significant error in tracking rays of light.
On the other hand, where difficulty is found in visiting medical care providers or spectacles shops such as due to the time required and the distance traveled for the visit, there has been a need for implementing a system which enables one to remotely measure his/her vision over the Internet.
In particular, a person's current spectacles or contact lenses may no longer properly correct their vision. In this case, it would be very convenient to remotely measure his/her uncorrected and corrected vision in order to determine whether he/she needs to buy new spectacles or contact lenses.
Moreover, if a user can see himself/herself wearing spectacles or contact lenses when selecting spectacles or contact lenses, the selection of spectacles or contact lenses is facilitated.